Here's the thing: when a big new device comes out, there can be something of a Pavlovian response. You see it, it's new, it's shiny (often literally shiny), and you want it. And of course, that's precisely the reaction that the people behind the device want you to have. Apple's great at this.

That's not to denigrate Apple's products, mind you. But how much difference does speed really make? If you have a smartphone -- even one that isn't fresh on the market -- it's probably pretty fast already. So what difference will faster make?

Glenn Fleishman writes about technology for The Economist's website and has authored several books on Apple. He says, "You can't read your email faster. Sorry, your eyes and brain only work at a certain speed. But it'll be better for photo editing if you want to edit photos in any apps available for iPhone, and there's some built-in photo editing now with iPhone 4S. It's going to shoot 1080p HD video, and you'll need more processing power."

So in lots of applications you won't notice it. But the appearance of speed may be just as important as speed itself, says Fleishman. "Apple and Google and all the other smartphone makers have tried to do things like provide quick transitions. So you think it's happening fast, even when it's happening slow on your smartphone. You only notice when when you're doing specific activities like trying to shoot HD video or play a realistic game."

Besides being faster, the iPhone 4S is supposedly smarter. It has a system called Siri which lets you give voice commands, ask questions, get answers. Boris Katz of MIT's Computer Science and Artificial Intelligence Laboratory worked on IBM's Watson project. That was the question-and-answer computer system that won on "Jeopardy."

Katz says there's already a lot of artificial intelligence being worked into daily life. He says, "Recent successes include things like object recognition systems that you can find in Google goggles or question answering systems that you can see in the Watson system at IBM. Or the iPhone intelligent assistant Siri."

But artificial intelligence, or A.I., is still at the Wright Brothers stage of development, says Katz. "The really huge problem that A.I. tried to address is to understand human intelligence," he says, "not just to build successful gadgets that simulate intelligence. We unfortunately are quite a long way from that. If you talk about Watson as an example, it's a fantastic engineering achievement, remarkable performance, but they certainly have not created a machine that thinks like us, like humans. And they did not bring us much closer to understanding human intelligence. This should be our next challenge."

Also in today's show, a new vocabulary word: graymail. That's the email that isn't quite spam but not quite the good email either. Microsoft is taking steps to better filter graymail out of your Hotmail account.